Yes they are, so much so, that I expect to be in every drama I watch 
Yeah, you are right. It makes sense for office workers, students, etc. to get Subway, but don’t kitchens usually assign someone to make lunch for that day? (a friend of mine works as a chef) I can’t image them going to a Subway, when they have better options that are probably cheaper 
I completely agree with @irmar about the beauty products - they really come off as marketing plots. I remember watching a historical drama where one of the characters got a tooth ache and someone advised her to use this new inventive cream that gets rid of that pain for you (some sort of toothache). That was so unexpected, that it was comical. I could something like that. But in most of the cases, even with face masks, most of the characters take the face masks off straight away or when they put a product on, f.e. moisturizer, they use on squirt and dab it on (I don’t use that little).
And the scene you pointed on in 17 but 30, also really stood out to me 
I don’t think I would never by a product that they advertise, but I wouldn’t actively seek them out either. Unless the product is already on my ‘research list’, then I wouldn’t really bother.